Search

Abstract: Objective: Tooth agenesis is the most common dental anomaly, whose aetiology still remains to be fully elucidated. The aim of this study was to investigate the genetic cause of non-syndromic hypodontia with clinical variability in an Egyptian family. Design: The entire coding regions including exon-intron boundaries of the MSX1, PAX9 and WNT10A genes were investigated by direct sequencing in all affected family members. Results: Novel heterozygous mutation inherited in an autosomal dominant manner was identified in the WNT10A gene. This 21-bp deletion combined with 1-bp insertion, c.-14_7delinsC, eliminates the translation initiation codon leading to either no protein production or translation of alternative open reading frames. None of the control subjects (400 chromosomes) were carriers of this novel WNT10A mutation. No pathogenic mutations were found in the MSX1 and PAX9 genes. Conclusions: The novel c.-14_7delinsC mutation might be the etiological variant of the WNT10A gene responsible for the permanent tooth agenesis in the Egyptian family. WNT10A is a major candidate gene for non-syndromic hypodontia. [Copyright &y& Elsevier]

Abstract: Background: Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common structural malformation with a complex and multifactorial aetiology. Associations of abnormalities in phenylalanine metabolism and orofacial clefts have been suggested. Methods: Eight single nucleotide polymorphisms (SNPs) of genes encoding phenylalanine hydroxylase (PAH) and large neutral l-amino acid transporter type 1 (LAT1), as well as the PAH mutation that is most common in the Polish population (rs5030858; R408W), were investigated in 263 patients with NSCL/P and 270 matched controls using high resolution melting curve analysis (HRM). Results: We found that two polymorphic variants of PAH appear to be risk factors for NSCL/P. The odds ratio (OR) for individuals with the rs7485331 A allele (AC or AA) compared to CC homozygotes was 0.616 (95% confidence interval [CI]=0.437–0.868; p =0.005) and this association remains statistically significant after multiple testing correction. The PAH rs12425434, previously associated with schizophrenia, was borderline associated with orofacial clefts. Moreover, haplotype analysis of polymorphisms in the PAH gene revealed a 4-marker combination that was significantly associated with NSCL/P. The global p-value for a haplotype comprised of SNPs rs74385331, rs12425434, rs1722392, and the mutation rs5030858 was 0.032, but this association did not survive multiple testing correction. Conclusion: This study suggests the involvement of the PAH gene in the aetiology of NSCL/P in the tested population. Further replication will be required in separate cohorts to confirm the consistency of the observed association. [Copyright &y& Elsevier]

Abstract: Objective: Overexpression of DNA methyltransferase 3A (DNMT3A) and aberrant methylation of various genes in eutopic endometrium have been demonstrated in women with endometriosis. We aimed to study whether DNMT3A polymorphisms could be a genetic risk factor for endometriosis and endometriosis-related infertility. Study design: We studied 5 SNPs (rs2289195, rs7590760, rs13401241, rs749131 and rs1550117) located in the DNMT3A gene in 357 women with endometriosis and 640 controls. Results: We did not observe significant differences between genotype and allele frequencies of rs2289195, rs7590760, rs13401241, rs749131 and rs1550117 SNPs in women with endometriosis, endometriosis-related infertility, and controls. The lowest p values of the trend test were observed for DNMT3A rs1550117 in endometriosis and endometriosis-related infertility (p trend =0.049 and p trend =0.055, respectively). Conclusions: Our results did not supply evidence for the contribution of SNPs located in DNMT3A to either endometriosis or endometriosis-related infertility. [Copyright &y& Elsevier]

Abstract: Objective: Tooth agenesis is the most common developmental anomaly of the human dentition, with aetiology involving both genetic and environmental factors. The aim of the study was to search for casual mutations underlying hypodontia in a family with agenesis of the second premolars and third molars. Design: Direct sequencing of the coding regions including exon–intron boundaries of the MSX1 and PAX9 genes was performed in all affected family members. Results: Novel heterozygous mutation segregating in an autosomal dominant model was identified in the MSX1 gene. This c.T671C transition leads to a substitution of leucine by proline at position 224, which is the penultimate amino acid residue of the highly conserved homeodomain. None of the control subjects (600 chromosomes) were carriers of this novel, probably damaging to protein function, mutation. Conclusions: Our results demonstrate for the first time that MSX1 might play a substantial role in familial cases of hypodontia involving only second premolars and third molars. The novel c.T671C mutation might be the etiological variant of the MSX1 gene responsible for the lack of permanent teeth in the tested family. [Copyright &y& Elsevier]

Abstract: Objective: Endometriosis has been considered an epigenetic disease. Single nucleotide polymorphisms (SNPs) located in genes encoding enzymes of the folate and choline metabolism may affect DNA methyltransferase activity. Study design: We studied 16 SNPs in 12 folate and choline metabolism genes, including BHMT (rs7356530 and rs3733890), BHMT2 (rs625879), CBS (844ins68), CHDH (rs893363 and rs2289205), CHKA (rs7928739), MTHFD1 (rs2236225), MTHFR (rs1801133), MTR (rs1805087), MTRR (rs1801394), PCYT1A (rs712012 and rs7639752), PEMT (rs4244593 and rs4646406) and TCN (rs1801198) in one hundred and sixty-three infertile women with minimal endometriosis and one hundred and fifty fertile women. Results: There were no significant differences between genotype and allele frequencies of these gene variants in infertile women with endometriosis (n =163) and controls (n =150). The lowest, but not statistically significant, p values of the trend test were observed for the CBS 844ins68 and MTR rs1805087 (p trend =0.0527 and p trend =0.0771, respectively) polymorphisms. However, the exhaustive multifactor dimensionality reduction analysis revealed an epistatic interaction between rs1801133 of MTHFR and rs4244593 of PEMT in endometriosis-associated infertility (p =0.0240). Conclusions: Our results showed moderate evidence for the contribution of SNPs located in genes encoding folate and choline metabolism enzymes to infertility in women with endometriosis. [Copyright &y& Elsevier]

Abstract: Objective: It has been reported that aberrant DNA methylation can be associated with HPV infection and cervical tumorigenesis. The aim of this study was to evaluate the possibility that polymorphic variants of genes that may affect DNA methylation status are associated with the risk of cervical cancer in the Polish population. Design and method: Employing PCR-RFLPs and HRM analyses, we examined the prevalence of BHMT Arg239Gln (rs3733890), MTR Asp919Gly (rs1805087), MTHFR Ala222Val (rs1801133), MTHFD1 Arg653Gln (rs2236225) and MTRR Ile22Met (rs1801394) genotypes and alleles in patients with advanced cervical cancer (n =124) and controls (n =168). Results: The odds ratio (OR) for BHMT Gln/Gln genotype was 0.433 (95% CI=0.1780–1.054; p =0.0602). The OR for patients having the BHMT Arg/Gln or Gln/Gln genotypes was 0.579 (95% CI=0.3622–0.924; p =0.0216). We also observed a significantly higher frequency of the BHMT 239Gln allele in controls than in patients, p =0.0165. The genotype and allele frequencies of the MTR Asp919Gly, MTHFR Ala222Val, MTHFD1 Arg653Gln and MTRR Ile22Met gene variants did not display statistical differences between patients with cervical cancer and controls. We also did not find a significant association between the distribution of any genotypes or alleles and cancer characteristics. Conclusion: Our results might suggest the protective role of the BHMT 239Gln variant in cervical cancer incidence. [Copyright &y& Elsevier]

Abstract: Objective: Maternal mid-pregnancy low levels of symmetric dimethylarginine and newborn low levels of citrulline are suspected to be risk factors for orofacial clefts. This study was undertaken to investigate the involvement of polymorphic variants of genes related to arginine metabolism in the susceptibility of clefting. Design: PCR-RFLP and HRM analyses were used to analyze single nucleotide polymorphisms (SNPs) of ASS1, ASL, and SLC25A13 in 172 children with non-syndromic cleft lip with or without cleft palate (CL/P) and 188 controls without congenital anomalies. The differences in allele and genotype frequencies between cases and controls were determined using standard Chi-square and Fisher exact tests. The odds ratio (OR) and associated 95% confidence intervals (95% CI) for individuals with CL/P versus controls were also calculated. Associations between the investigated polymorphisms and the risk of being born with an orofacial cleft were tested using the nonparametric and genetic model-free Multifactor Dimensionality Reduction (MDR) approach. Results: Analysis of five SNPs of the ASS1 gene revealed that the G allele of rs7860909 is associated with increased CL/P risk. Compared to individuals with the AA genotype, the G allele carriers had an OR of 1.768 (95% CI: 1.133–2.759; p =0.012). For the remaining SNPs of all analysed genes, there was no overall evidence for cleft association considering the allele and genotype distribution. However, gene-by-gene interaction analysis conducted using the MDR approach revealed a significant interactive genetic effect of ASS1 (rs666174) and SLC25A13 (rs10252573) on the occurrence of clefting (p =0.002). Conclusion: Our results demonstrate moderate evidence for the association of polymorphic variants of genes related to arginine metabolism with abnormal palatogenesis. [ABSTRACT FROM AUTHOR]

Abstract: Objective: : The study focused on the correlation between maternal polymorphisms of genes encoding antioxidant enzymes and the risk of having a child with CL/P in the Polish population. Method: : PCR–RFLP analysis was used to analyze polymorphisms of MnSOD 2 (c.47T>C), CAT (c.−330C>T) and GPX1 (c.599C>T) in mothers of children with CL/P and control mothers. Results and Conclusion: : Polymorphic variants of genes for main antioxidant enzymes were determined not to be a maternal risk factor for having a child with CL/P in the investigated group of women. [Copyright &y& Elsevier]

Abstract: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphism 677C>T has been shown to be a risk factor for psychiatric disorders. We investigated the genotype and allelic frequencies of MTHFR 677C>T polymorphism in the group of patients with bipolar disorder type I (BDI) (n =200) and schizophrenia (n =200), and in the control group (n =300). Odds ratio (OR) for patients with BD and schizophrenia with 677T allele was 1.988 ((95% CI=1.370–2.883); P =0.0003 (P =0.0006 after Bonferroni correction)) and 1.796 ((95% CI=1.237–2.609); P =0.0020 (P =0.0040 after Bonferroni correction)), respectively. The stratification of patients based on gender revealed significant association of 677T allele with male patients with BDI and schizophrenia (OR=2.393; 95% CI=1.429–4.006; P =0.0008 and OR=2.036; 95% CI=1.207–3.433; P =0.0073, respectively). This finding indicates possible association of BD and schizophrenia with the 1p36.3 MTHFR locus. [Copyright &y& Elsevier]

This article examines the life stories of two young Polish women who have faced severe marginalization and homelessness. The main aim of this article is to investigate how the notions of (in)visibility and (im)mobility are shaping participants' everyday lives and life stories they tell. Using concepts drawn from social sciences, as well as cultural and literary studies, this article attempts to reconstruct the narrative frameworks of their life stories. Marzena's story is a non-linear collection of adventures reminiscent of a picaresque novel, but with fractured agency, which leaves her powerless and restlessly moving around the city. Angelika, on the other hand, is trapped in a two-room dilapidated house with no running water, located in a rural part of Poland. Her narrative resembles a telenovela with melodramatic plot twists, romance and hard-to-believe revelations about the narrator's true self; further, it is a purposeful journey in search for happiness and fortune. Surprisingly, Marzena's mobility makes it unlikely for her to overcome homelessness, while the stranded Angelika finds the resilience necessary to improve her life. The proposed analysis contributes to a deeper understanding of women's experiences of homelessness and demonstrates the need to regard housing exclusion also as a biographical process. • We examine life stories of two young women experiencing housing exclusion in Poland. • The first narrative is a non-linear collection of urban trickster's adventures. • The second narrative is a telenovela-like fairy tale of a poor rural girl. • We show how the dimensions of (in)visibility are shaping their everyday lives. • The narratives reflect also the regional contexts and women's spatial (im)mobility. [ABSTRACT FROM AUTHOR]

Aim To investigate circulating IFN-λ3 and IFNL3 polymorphisms in hemodialysis (HD) patients differing in HBV surface antigen antibody (anti-HBs) production. Methods The study included 106 HBV-vaccinated HD patients (88 developed anti-HBs) and 36 HBV-infected HD subjects (27 developed anti-HBs). Plasma IFN-λ3 (enzyme-linked immunosorbent assay) and rs12979860 (C > T) and rs8099917 (T > G) in IFNL3 (high-resolution melting curve analysis) were analyzed with regard to the association with anti-HBs production in response to HBV vaccination or infection. The results were adjusted for gender, age, cause of renal disease, dialysis vintage, dialysis modality, IFN-λ3, and 25(OH)D as appropriate. Results HBV vaccine responders had higher circulating IFN-λ3 (ng/L) than non-responders (120, 36–233 vs. 53, 33–109, P < 0.000001). Patients who generated anti-HBs after HBV infection also had higher circulating IFN-λ3 levels than those who did not (133, 35–215 vs. 71, 9–229, P = 0.043). The IFN-λ3 concentration correlated with the anti-HBs titer in vaccinated (r = 0.614, P < 0.000001) and infected patients (r = 0.589, P = 0.0002). Plasma IFN-λ3 was the only significant indicator of responsiveness to HBV vaccination (adjusted P = 0.018) and remained the only significant associate for the development of post-infection anti-HBs (adjusted P = 0.049). A plasma IFN-λ3 level of 85.5 ng/L was the cut-off value for the prognosis of an anti-HBs titer below vs. equal to or over 10 IU/L in the entire group of HD patients (ROC sensitivity 68.7%, specificity 85.2%, and AUC 0.827). Significant associations were not found between IFN-λ3 and IFNL3 rs12979860. Subjects treated with low flux HD that harbored the TT genotype in rs8099917 showed higher IFN-λ3 levels than patients bearing the G allele in rs8099917 (139, 68–233 vs. 103, 9–208, P = 0.049). Conclusion In HD patients, circulating IFN-λ3 strongly correlates with anti-HBs production after HBV vaccination and infection. IFNL3 rs8099917 polymorphisms seem to be associated with IFN-λ3 plasma levels in HD subjects. [ABSTRACT FROM AUTHOR]

Aims We examined the involvement of plasma adropin and adropin-associated genes ( ENHO and RXRA ) in metabolic abnormalities of hemodialysis (HD) patients. Main methods Among 50 HD patients (27 males and 23 females, aged 65.2 ± 12.6 years, HD vintage 29.0, 3.9–157.0 months), there were 26 dyslipidemics and 25 type 2 diabetics. Age-matched healthy subjects ( n = 26) served as controls. Adropin levels were determined using ELISA. Insulin resistance/sensitivity was assessed using the Homeostasis Model Assessment for Insulin Resistance and Quantitative Insulin Sensitivity Check Index. ENHO (rs2281997, rs72735260) and RXRA (rs10881578, rs10776909) were genotyped by HRM, RXRA rs749759 by PCR-RFLP. Circulating adropin, serum lipids, and insulin indices were compared between bearers of the minor allele of tested polymorphisms and major homozygotes (the dominant model of inheritance). Key findings HD patients showed lower circulating adropin concentration compared with controls. In dyslipidemic patients, plasma adropin was lower than that in non-dyslipidemics, but it was not significantly different in diabetics vs. non-diabetics or in patients with or without metabolic syndrome. Major homozygotes of ENHO rs2281997 seemed to have higher circulating adropin, whereas major homozygotes of RXRA (rs749759, rs10776909) showed lower levels. Major homozygotes of ENHO rs2281997 showed borderline lower insulin resistance compared with bearers of the minor allele. Significance In HD patients, lower plasma adropin concentration is associated with dyslipidemia. Major homozygosity of RXRA seems to have an opposite effect on plasma adropin compared with that of ENHO rs2281997. [ABSTRACT FROM AUTHOR]

Background Indoleamine 2,3-dioxygenase (IDO) contributes to maintaining immune homeostasis. Polymorphisms (SNPs) of the IDO encoding gene ( IDO1 ) influence the IDO activity. Interferon (IFN)-λ3 induces IDO expression. We aimed to investigate whether IDO1 variants are associated with anti-HBs production in response to HBV vaccination or infection, interact with IFN-λ3 associated variants of IFNL4 , and influence survival of hemodialysis (HD) patients. We also tested circulating IDO concerning IDO1 SNPs and plasma IFN-λ3 and anti-HBs levels. Methods The study included HD patients who had established status concerning responsiveness to HBV vaccination (n = 1022) or were exposed to HBV (n = 315). Ability to generate anti-HBs was diagnosed if anti-HBs after vaccination or infection exceeded 10 IU/L. Genotyping of IDO1 (rs3739319 A < G, rs9657182 C < T), IFNL4 rs8099917 G < T and IFNL4 rs12979860 C > T polymorphisms was carried out by high-resolution melting curve analysis. Circulating IDO and IFN-λ3 were measured with ELISA in 57 subjects. Survival probability was analyzed using the Kaplan-Meier method. Results IDO1 SNPs did not correlate with the ability to produce anti-HBs after vaccination or infection. Anti-HBs titers, including a frequency of anti-HBs ≥ 1000 IU/l, also did not associate with IDO1 SNPs, but there was an epistatic interaction between rs9657182, rs8099917, and rs12979860 concerning anti-HBs titers (P = 0.028). Significant associations between IDO1 SNPs and circulating IDO were not demonstrated. Anti-HBs titers negatively correlated with plasma IDO (r = −0.358, P = 0.006), and positively with circulating IFN-λ3 (r = 0.498, P = 0.00008). IDO and IFN-λ3 did not correlate. Patients possessing the rs9657182 TT genotype showed higher infection-related mortality, also in multivariate analysis (HR 2.073, 1.221–3.518, P = 0.007). Conclusions IDO1 rs9657182, IFNL4 rs8099917, and IFNL4 rs12979860 show epistatic interaction concerning anti-HBs titers. Overreacting immune responses to HBsAg occur in patients with lower IDO but simultaneously higher IFN-λ3 levels. The rs9657182 TT genotype associates with infection-related mortality of HD patients. [ABSTRACT FROM AUTHOR]

Lipoxygenases (LOXs) are non-haem iron-containing dioxygenases that catalyse oxygenation of polyunsaturated fatty acids. This reaction is the first step in biosynthesis of oxylipins, which play important and diverse roles in stress response. In this study, we identified four LOX genes ( PcLOXA, B, C, D ) in chilling-sensitive runner bean ( Phaseolus coccineus L.) plant and analyzed their expression patterns during long term dark-chilling (4 °C) stress and during day/night (21ºC/4 °C) temperature fluctuations. Three of the four identified LOX genes, namely PcLOXA , PcLOXB and PcLOXD, were induced by wounding stress, while only the PcLOXA was induced by dark-chilling of both detached (wounded) leaves and whole plants. We identified PcLOXA as a chloroplast-targeted LOX protein and investigated its expression during chilling stress in terms of abundance, localization inside chloroplasts and interactions with the thylakoid membranes. The analysis by immunogold electron microscopy has shown that more than 60% of detectable PcLOXA protein was associated with thylakoids, and dark-chilling of leaves resulted in increased amounts of this protein detected within grana margins of thylakoids. This effect was reversible under subsequent photo-activation of chilled leaves. PcLOXA binding to thylakoids is not mediated by the posttranslational modification but rather is based on direct interactions of the protein with membrane lipids; the binding strength increases under dark-chilling conditions. [ABSTRACT FROM AUTHOR]

Plants in a temperate climate are often subject to different environmental factors, chilling stress among them, which influence the growth especially during early stages of plant development. Chloroplasts are one of the first organelles affected by the chilling stress. Therefore the proper biogenesis of chloroplasts in early stages of plant growth is crucial for undertaking the photosynthetic activity. In this paper, the analysis of the cotyledon chloroplast biogenesis at different levels of plastid organization was performed in cucumber, one of the most popular chilling sensitive crops. Influence of low temperature on the ultrastructure was manifested by partial recrystallization of the prolamellar body, the formation of elongated grana thylakoids and a change of the prolamellar body structure from the compacted “closed” type to a more loose “open” type. Structural changes are strongly correlated with galactolipid and carotenoid content. Substantial changes in the galactolipid and the carotenoid composition in dark-chilled plants, especially a decrease of the monogalactosyldiacylglycerol to digalactosyldiacylglycerol ratio (MGDG/DGDG) and an increased level of lutein, responsible for a decrease in membrane fluidity, were registered together with a slower adaptation to higher light intensity and an increased level of non-photochemical reactions. Changes in the grana thylakoid fluidity, of their structure and photosynthetic efficiency in developing chloroplasts of dark-chilled plants, without significant changes in the PSI/PSII ratio, could distort the balance of photosystem rearrangements and be one of the reasons of cucumber sensitivity to chilling. [ABSTRACT FROM AUTHOR]

Objective Mutations in the EDA gene, encoding the epithelial morphogen ectodysplasin-A, can result in different but overlapping phenotypes. Therefore the aim of the study was to search for etiological variations of EDA and other candidate genes in two unrelated Egyptian male children with sporadic non-syndromic tooth agenesis (NTA) and hypohidrotic ectodermal dysplasia (HED). Design Direct sequencing of the coding regions including exon-intron boundaries of EDA , MSX1 , PAX9 , WNT10A and EDAR was performed in probands and their available family members. Results Two etiological mutations were found in the EDA coding region. The patient with NTA in both deciduous and permanent dentition was a carrier of a novel in-frame deletion situated in the short collagenous domain (c.663-680delTCCTCCTGGTCCTCAAGG, p.222-227delPPGPQG). The second mutation, located outside the minimal furin consensus motif (c.463C>T, p.Arg155Cys, rs132630312), was identified in the patient exhibiting all typical features of HED. The identified EDA mutations were not detected in probands’ family members as well as in 188 unrelated control individuals. No pathogenic variants were found in the MSX1 , PAX9 , WNT10A and EDAR genes. Conclusion Our results increase the knowledge of the spectrum of EDA mutations and confirm that this gene is an important candidate gene for two developmental diseases sharing the common feature of the congenital lack of teeth. In addition, these results can support the hypothesis that X-linked HED and EDA-related NTA are the same disease with different degrees of severity. [ABSTRACT FROM AUTHOR]

Abstract: We searched for an association between the interleukin 4 receptor gene (IL4R) rs1805015 and interleukin 13 gene (IL13) rs20541 polymorphisms and the development of antibodies to hepatitis B surface antigen (anti-HBs) in the case of hepatitis B virus (HBV) vaccination or infection in hemodialysis (HD) patients. HD patients who failed to respond to HBV vaccination did not differ in genotype frequencies of IL4R (TT 72.7%, CT 22.6%, CC 4.7%) and IL13 (CC 59.0%, CT 34.2%, TT 6.8%) from vaccine responders (IL4R TT 68.0%, CT 27.3%, CC 4.7%; IL13 CC 55.0%, CT 38.5%, TT 6.5%). HD patients who did not develop anti-HBs despite HBV infection also did not differ in genotype frequencies of IL4R (TT 67.8%, CT 26.8%, CC 5.4%) and IL13 (CC 60.7%, CT 33.9%, TT 5.4%) from HD patients who developed an anti-HBs response (IL4R TT 65.4%, CT 30.8%, CC 3.8%; IL13 CC 60.5%, CT 34.6%, TT 4.9%). In HD patients, neither the IL4R nor IL13 polymorphism is associated with anti-HBs development irrespective of whether an immunization is provoked by HBV vaccination or HBV infection. [Copyright &y& Elsevier]

Abstract: Chloroplast biogenesis is a multistage process leading to fully differentiated and functionally mature plastids. Complex analysis of chloroplast biogenesis was performed on the structural and functional level of its organization during the photoperiodic plant growth after initial growth of seedlings in the darkness. We correlated, at the same time intervals, the structure of etioplasts transforming into mature chloroplasts with the changes in the photosynthetic protein levels (selected core and antenna proteins of PSI and PSII) and with the function of the photosynthetic apparatus in two plant species: bean (Phaseolus vulgaris L.) and pea (Pisum sativum L). We selected these plant species since we demonstrated previously that the mature chloroplasts differ in the thylakoid organization. We showed that the protein biosynthesis as well as photosynthetic complexes formation proceeds gradually in both plants in spite of periods of darkness. We found that both steady structural differentiation of the bean chloroplast and reformation of prolamellar bodies in pea were accompanied by a gradual increase of the photochemical activity in both species. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. [Copyright &y& Elsevier]

Abstract: We performed for the first time three-dimensional (3D) modelling of the entire chloroplast structure. Stacks of optical slices obtained by confocal laser scanning microscope (CLSM) provided a basis for construction of 3D images of individual chloroplasts. We selected pea (Pisum sativum) and bean (Phaseolus vulgaris) chloroplasts since we found that they differ in thylakoid organization. Pea chloroplasts contain large distinctly separated appressed domains while less distinguished appressed regions are present in bean chloroplasts. Different magnesium ion treatments were used to study thylakoid membrane stacking and arrangement. In pea chloroplasts, as demonstrated by 3D modelling, the increase of magnesium ion concentration changed the degree of membrane appression from wrinkled continuous surface to many distinguished stacked areas and significant increase of the inter-grana area. On the other hand 3D models of bean chloroplasts exhibited similar but less pronounced tendencies towards formation of appressed regions. Additionally, we studied arrangements of thylakoid membranes and chlorophyll–protein complexes by various spectroscopic methods, Fourier-transform infrared spectroscopy (FTIR) among others. Based on microscopic and spectroscopic data we suggested that the range of chloroplast structure alterations under magnesium ions treatment is a consequence of the arrangement of supercomplexes. Moreover, we showed that stacking processes always affect the structural changes of chloroplast as a whole. [ABSTRACT FROM AUTHOR]

Abstract: Changes in chloroplast structure and rearrangement of chlorophyll–protein (CP) complexes were investigated in detached leaves of bean (Phaseolus vulgaris L. cv. Eureka), a chilling-sensitive plant, during 5-day dark-chilling at 1 °C and subsequent 3-h photoactivation under white light (200 μmol photons m−2 s−1) at 22 °C. Although, no change in chlorophyll (Chl) content and Chl a/b ratio in all samples was observed, overall fluorescence intensity of fluorescence emission and excitation spectra of thylakoid membranes isolated from dark-chilled leaves decreased to about 50%, and remained after photoactivation at 70% of that of the control sample. Concomitantly, the ratio between fluorescence intensities of PSI and PSII (F736/F681) at 120 K increased 1.5-fold upon chilling, and was fully reversed after photoactivation. Moreover, chilling stress seems to induce a decrease of the relative contribution of LHCII fluorescence to the thylakoid emission spectra at 120 K, and an increase of that from LHCI and PSI, correlated with a decrease of stability of LHCI–PSI and LHCII trimers, shown by mild-denaturing electrophoresis. These effects were reversed to a large extent after photoactivation, with the exception of LHCII, which remained partly in the aggregated form. In view of these data, it is likely that dark-chilling stress induces partial disassembly of CP complexes, not completely restorable upon photoactivation. These data are further supported by confocal laser scanning fluorescence microscopy, which showed that regular grana arrangement observed in chloroplasts isolated from control leaves was destroyed by dark-chilling stress, and was partially reconstructed after photoactivation. In line with this, Chl a fluorescence spectra of leaf discs demonstrated that dark-chilling caused a decrease of the quantum yield PSII photochemistry (F v/F m) by almost 40% in 5 days. Complete restoration of the photochemical activity of PSII required 9 h post-chilling photoactivation, while only 3 h were needed to reconstruct thylakoid membrane organization and chloroplast structure. The latter demonstrated that the long-term dark-chilled bean leaves started to suffer from photoinhibition after transfer to moderate irradiance and temperature conditions, delaying the recovery of PSII photochemistry, independently of photo-induced reconstruction of PSII complexes. [Copyright &y& Elsevier]

Aims: Data on involvement of paraoxonase 1 gene (PON1) in non-insulin-dependent diabetes mellitus (NIDDM) nephropathy are scarce. We investigated PON1 polymorphisms concerning end-stage NIDDM nephropathy and atherosclerotic complications in NIDDM nephropathy patients treated with hemodialysis (HD).Methods: In NIDDM nephropathy (n = 402) and non-diabetic (n = 998) HD subjects, we obtained PON1 polymorphisms by HRM analysis (rs662) or predesigned TaqMan SNV Genotyping Assay (rs854560, rs705379).Results: Only PON1 rs705379 was associated with end-stage NIDDM nephropathy in the recessive (OR 1.451, 95% CI 1.104-1.906, P = 0.009) and additive (OR 1.398, 95%CI 1.009-1.936, P = 0.046) inheritance modes. NIDDM nephropathy patients bearing the rs854560 T allele were at higher risk for ischemic cerebral stroke (OR 2.087, 95%CI 1.145-3.801, P = 0.016). In non-diabetic patients but not NIDDM nephropathy subjects, atherogenic dyslipidemia corresponded with PON1 rs662 A allele and PON1 rs854560 TT homozygosity.Conclusions: In HD patients, NIDDM nephropathy correlates with the TT genotype of PON1 rs705379. The rs854560 T allele indicates a higher risk for atherosclerotic diseases in NIDDM nephropathy subjects. The T alleles of both PON1 SNVs are known as low expression variants downregulated serum PON1 activity. An increase of diminished PON1 activity may be a target in the prevention of NIDDM nephropathy and NIDDM atherosclerotic complications. [ABSTRACT FROM AUTHOR]